A brain stroke occurs when blood supply to the brain is reduced or interrupted, depriving brain cells of oxygen and nutrients and potentially causing cell death. Strokes are medical emergencies that require immediate treatment to minimize brain damage and maximize chances of survival. The two main types of strokes are ischemic, caused by a blocked artery, and hemorrhagic, caused by a burst blood vessel. Risk factors include conditions like obesity, hypertension, smoking, and atrial fibrillation. Diagnosis involves tests like CT/MRI scans and treatment depends on the stroke type but generally focuses on restoring blood flow and preventing further damage. Ongoing rehabilitation is also important for recovery.